At present, not only patients suffering from diseases but also healthy persons undergo various medical practices such as medical examinations. For example, injections are used for the patients suffering from diseases, for the purpose of injecting a liquid medicine for therapy, anesthesia at the time of surgery, or the like. In addition, even healthy persons often undergo injections such as blood donation and preventive inoculation. However, injections exert considerable burden on patients and healthy persons, due to a pain at the time of puncture, discomfort at the time of injection of a liquid medicine, or the like. In view of this, for the purpose of alleviating the pain, a variety of investigations have been made on the shape of tip portions of injection needles, coating agents for injection needle surfaces, and the like. Among these, as a coating agent for injection needle surfaces, silicones have been mainly used. The silicone coating agents impart a lubricating property to the injection needle, thereby reducing friction at the time of puncture. Therefore, an injection needle coated with a silicone coating agent alleviates the pain at the time of injection. For example, Japanese Patent Laid-open No. 1995-178159 discloses a silicone coating agent that contains an amino-group-containing polyorganosiloxane and a polydiorganosiloxane in a specific mixing ratio. An injection needle coated with this coating agent exhibits excellent piercing characteristics.